Abstract
Travel diary is one of the fundamental methods for collecting data critical for transportation planning, demand modelling, and analyses. Self-reported household travel surveys are known for recall and proxy biases. Both biases lead to underreporting of travel demand in the dataset. On the other hand, travel diaries collected through GPS-based methods are exempted from recall and proxy biases. Thus, this study will investigate the recall and proxy bias in self-reported travel surveys and propose correction procedures. The investigation and correction will be conducted under the core-satellite paradigm of urban passenger travel surveys under the core-satellite survey design paradigm. The study uses the Transportation Tomorrow survey (TTS) in the Greater Toronto and Hamilton area (GTHA) as the core dataset. The Google Timeline Travel Survey (GTTS) will be used as the satellite survey. The direct comparison between the core and satellite surveys shows that respondents who participated in both TTS and GTTS demonstrated bias-free diary reporting in the self-reported core survey. However, significant recall and proxy bias are identified for individuals who directly participate in the TTS but refuse to participate in GTTS and the proxy respondents in the TTS. Then, this study proposes a correction procedure based on respondents’ willingness-to-participate estimation for satellite surveys, dataset filtration, and re-weighting techniques. The effectiveness of the correction procedure is empirically demonstrated in this study.